The present invention relates to an autofocus system for cameras with a separator to divide the object in an autofocus measuring field viewed through the camera lens into two beams to determine the distance of the object from the film plane and with a control system to control the focusing of the camera lens which sets the focus of the camera lens in accordance with the measured distance by means of servomotors or similar.
Such autofocus systems are generally known in the art. All autofocus systems used to date comprise an autofocus measuring field which is comparatively small and lies in the centre of the image. Consequently, the object on which the camera is to focus must also be located exactly in the centre of the image. In some technically more sophisticated cameras this disadvantage is overcome in that the set focus can be stored in a memory, although with some systems this is only possible for the duration of a single frame. Only if this supplementary memory is used is it possible for the object also to be positioned outside the centre of the image and for the shutter then to be released. This solution is only practicable, however, if the object does not move, i.e. it remains within the focus range once this has been determined. Otherwise, the whole focusing process must be repeated which is completely impossible, for example, with constantly moving objects. It has thus been shown in practive that both precise light metering and reliable focusing by means of the autofocus system can only be achieved in an uncomplicated fashion on condition that the object to be photographed exhibits little movement and is located exactly in the centre of the frame. Freer picture composition is only possible by means of storing the readings, although this compromise is not possible with moving objects, as a result of which all the advantages of automatic light metering and focusing are nullified.